aDepartment of Psychology, 5057 Woodward Avenue-7th Floor, Wayne State University, Detroit, MI 48202, USA bResearch Department of Clinical, Educational & Health Psychology, University College London, Gower Street, London WC1E 6BT, UK *Corresponding author. Tel.: +1 313 577 1492; fax: +1 313 577 7636. E-mail addresses:[email protected], [email protected] Submitted February 20, 2009; revised July 30, 2009; accepted October 14, 2009.